Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

Identifying the best iron-peak and α-capture elements for chemical tagging: The impact of the number of lines on measured scatter

V. Zh. Adibekyan, P. Figueira, N. C. Santos, S. G. Sousa, J. P. Faria, E. Delgado Mena, M. Oshagh, M. Tsantaki, A. A. Hakobyan, J. I. González Hernández, L. Suárez-Andrés, G. Israelian

Abstract
Aims. The main goal of this work is to explore which elements carry the most information about the birth origin of stars and, as such, which are best suited for chemical tagging.
Methods.
We explored different techniques to minimize the effect of outlier value lines in the abundances by using Ni abundances derived for 1111 FGK-type stars. We evaluate how the limited number of spectral lines can affect the final chemical abundance. Then we make an efficient even footing comparison of the [X/Fe] scatter between the elements that have a different number of observable spectral lines in the studied spectra.
Results.
When several spectral lines are available, we find that the most efficient way of calculating the average abundance of elements is to use a weighted mean (WM), whereby we consider the distance from the median abundance as a weight. This method can be used effectively without removing suspected outlier lines. When the same number of lines are used to determine chemical abundances, we show that the [X/Fe] star-to-star scatter for iron group and α-capture elements is almost the same. The largest scatter among the studied elements, was observed for Al and the smallest for Cr and Ni.
Conclusions.
We recommend caution when comparing [X/Fe] scatters among elements where a different number of spectral lines are available. A meaningful comparison is necessary to identify elements that show the largest intrinsic scatter, which can then be used for chemical tagging.

Keywords
stars: abundances - stars: general - stars: fundamental parameters

Astronomy and Astrophysics
Volume 583, Page A94
November 2015

>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website